Analog Electronic Circuits Questions and Answers – Diode Approximations and Series Connection

This set of Analog Circuits Multiple Choice Questions & Answers (MCQs) focuses on “Diode Approximations and Series Connection”.

1. Which of the following models of a semiconductor diode is the most widely used for the purpose of calculation?
a) Approximate Equivalent Model
b) Ideal Diode Model
c) Piecewise Linear Model
d) Hybrid model
View Answer

Answer: a
Explanation: Approximate Equivalent model not only saves time and efforts but also provides results with a considerable amount of accuracy.

2. Which of the following statement holds true?
Statement-1: Piecewise linear model is generally not used for diode analysis.
Statement-2: The value of Rav is negligible as compared to the load resistance.
a) Statement-1 is true, Statement-2 is true and Statement-2 is a proper explanation for Statement-1
b) Statement-1 is true, Statement-2 is true and Statement-2 is not a proper explanation for Statement-1
c) Statement-1 is true, Statement-2 is false
d) Statement-1 is false, Statement-2 is true
View Answer

Answer: a
Explanation: Piecewise linear model involves a line with a slope equal to 1/Rav. As Rav is low, 1/ Rav is high and the slope becomes almost equal to infinity and hence, it approaches the equivalent circuit model and hence, the piecewise linear model isn’t generally used.

3. From the given circuit diagram, considering the diode to be a silicon semiconductor diode, what is the magnitude of diode current? (Use an appropriate model of the diode)
Find the magnitude of diode current of silicon semiconductor diode
a) 43 mA
b) 0 mA
c) 4.3 mA
d) 5 mA
View Answer

Answer: c
Explanation: ID = (V-VD)/R = 4.3 mA.
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4. From the given circuit diagram, what is the value of diode current?
Find the value of diode current when diodes are reverse biased
a) 8 mA
b) 7.3 mA
c) 0 mA
d) 7 mA
View Answer

Answer: c
Explanation: As both the diodes are reverse biased, the current in the circuit is zero.

5. From the given circuit diagram, what is the value of diode current?
Find the value of diode current of reverse silicon diode in the circuit
a) 8 mA
b) 0 mA
c) 7.3 mA
d) 7 mA
View Answer

Answer: b
Explanation: As the silicon diode in the circuit is reverse biased, hence the current in the circuit is zero.
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6. From the given circuit diagram, what is the value of diode current? Use an appropriate diode model.
Find value of current having drop of 0.3V for Ge & 0.7V for Silicon in forward bias
a) 8 mA
b) 0 mA
c) 7.3 mA
d) 7 mA
View Answer

Answer: d
Explanation: The diodes have a drop of 0.3V for Ge and 0.7V for Silicon in forward bias. We can use the constant voltage model, and hence in forward bias, the current flowing is
ID = (V-VD1-VD2)/R = 7 mA.

7. From the given circuit diagram, what is the value of diode current?
Circuit having diodes in forward bias with total drops cancel out the source voltage
a) 2 mA
b) 0 mA
c) 1.3 mA
d) 1 mA
View Answer

Answer: b
Explanation: The diodes in forward bias, have drops of 0.3V for Ge and 0.7V for Si, and the total drops cancel out the source voltage, and hence the diode current is zero.
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8. From the given circuit diagram, what is the value of voltage across the resistor?
Find the value of voltage across the resistor when the diode current is zero
a) 2 V
b) 1.3 V
c) 1 V
d) 0 V
View Answer

Answer: d
Explanation: The diodes in forward bias, have drops of 0.3V for Ge and 0.7V for Si, and the total drops cancel out the source voltage, and hence the diode current is zero. Hence voltage drop is also zero.

9. From the given circuit diagram, what is the value of diode current?
Find the value of diode current in (V-VD)/R from the given circuit diagram
a) 2.425 mA
b) 5.2 mA
c) 2.325 mA
d) 0 mA
View Answer

Answer: c
Explanation: Here, ID=(V-VD)/R = 2.325 mA.
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10. From the given circuit diagram, what is the value of voltage across R2?
Find the value of diode current in I x R2 from the given circuit diagram
a) 9.324 V
b) 5.3 V
c) 0 V
d) 5.8125 V
View Answer

Answer: d
Explanation: Here, current I=10-0.7/4k=2.325 mA
Here, VR2 = I x R2 = 5.8125 V.

11. From the given circuit diagram, what is the voltage across diode?
Find the voltage across diode if voltage across the diode is equal to the source voltage
a) 10 V
b) 5 V
c) 0.7 V
d) 0 V
View Answer

Answer: a
Explanation: As the diode is reverse biased, the current in the circuit is zero and hence the voltage across the diode is equal to the source voltage = 10 V.

12. From the given circuit diagram, what is the value of diode current?
Find the voltage across diode if diode is reverse biased & current in circuit is zero
a) 2.425 mA
b) 5.2 mA
c) 2.325 mA
d) 0 mA
View Answer

Answer: d
Explanation: As the diode is reverse biased, the current in the circuit is zero.

Sanfoundry Global Education & Learning Series – Analog Circuits.

To practice all areas of Analog Circuits, here is complete set of 1000+ Multiple Choice Questions and Answers.

If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]

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